Standardisation of glutaraldehyde-modified tyrosine-adsorbed tree pollen vaccines containing the Th1-inducing adjuvant, monophosphoryl lipid A (MPL).

BACKGROUND a new range of allergy vaccines has been developed by the introduction of a relatively new Th1-inducing adjuvant known as 3-deacylated monophosphoryl lipid A (MPL). MPL adjuvant is of natural origin, derived from the lipopolysaccharide of Salmonella minnesota R595. This adjuvant is incorporated in a glutaraldehyde-modified pollen extract adsorbed to L-tyrosine (Pollinex Quattro). A major potential benefit provided by MPL adjuvant is the promotion of a Th1 response which enhances the efficacy of allergy vaccination and can consequently allow a reduction in the number of injections required for treatment. The standardisation of Pollinex Quattro tree pollen allergy vaccine is described and we include details of some innovative analytical procedures. METHODS AND RESULTS an essential feature of the analytical strategy is the assay of the MPL adjuvant using a recently developed HPLC technique. The adjuvant has a complex chemical structure and the analysis is illustrated in detail. We give a full picture of the vaccine standardisation by describing biochemical and immunological characterisation of the allergen extract, together with some brief manufacturing details. CONCLUSIONS a high overall level of standardisation is illustrated by a number of different tests applied to all stages of vaccine manufacture. Tree pollen allergen potency is measured following the pollen extraction, chemical modification and formulation as a tyrosine adsorbate. Good batch-to-batch reproducibility is shown. The HPLC assay for MPL adjuvant showed high quality resolution which did not vary when measuring raw material or when incorporated in the vaccine and the technically complex assay is shown to be reliable.